Was this a valid drug case conviction? Or was this a denial of a fair trial?

According to the AP news wire today, there was a court case in Cleaveland, where a federal judge refused to grant a new trial to three people convicted of dealing drugs.

(I'm not allowed to copy the actual story, so I'll just give a summary here.)

Apparently, U.S. District Judge James Gwin ruled that, while he did not approve of the way the government handled the case, the defendants failed to show prejudice in their original trials, and so would not be granted a second trial.

Now, this is, in a nutshell, exactly my issues with the federal court system. This country, alone, first, and (as far as I know) unique in the world, operates on the principal that the federal government is not all powerful, and cannot do whatever it wants. The 10th amendment makes it abundantly clear that the federal government is restricted. The 9th makes it clear that we start with the assumption of rights of people (and states). The preamble makes it clear that justice, rather than arbitrarily rulings, is the key. We've got the right of a jury trial stated multiple times.

Yet, rather than letting a jury hear this case, a judge said that, even though the judge did not like what was done, the people accused of a crime, and potentially convicted in error, could not prove that they were not given a fair trial. Not: The government must prove that they followed the rules. The accused, innocent until proven guilty, now have the additional burden of proving that the government failed to follow the rules. Not to a level of proof acceptable to a jury, but to a level that is more than required to convince a judge that something is wrong.

So what is the issue here? Get this. Sit down. Normally I cut these in my RSS feed; this time I'm not cutting this.

The DEA agent who provided testimony against them was on trial for putting false information in his reports.
He was aquitted.
The federal government withheld information/evidence that could have been used against this DEA agent.
The indication is fairly strong that had this evidence been presented, then either (A) the agent would have been found guilty, or (B) the evidence would have been considered tainted, and not permitted in this court case that found these three people guilty.

So, lets see if I understand this correctly:
1. DEA agent falsifies testamony. (a violation.)
2. Government has evidence that it refuses to turn over to the other side in a trial (a violation).
3. Government deliberately misrepresents the agent's work (a violation)
4. The judge agrees that the government did not act properly
5. The judge ruled that, because the prior trial was not proven to be in error, must be held acceptable.

So what possible standard of improper trial can possibly be held here?

Again: No jury was allowed to examine the question of "was this trial fair". The judge did not approve of the government's action. The government failed to provide a fair and unbiased trial. The government withheld evidence that would have harmed its case.

And the convictions were upheld.